MDB et al; clone cranks & crank supports?

[65ShelbyClone]

I remember that there have been several documented failures of clone cranks in built, high-RPM engines and that Honda cranks are preferred. Has anyone tried running the clones with a crank support? It seems to me that the power and RPM ceiling of a production part could probably be raised quite a bit for significantly less expense than a billet crank.

 

[minidragbike]

I have made one for my TopFuel motor. But there has been a lot of clone crank failures. I'm sure someone will make one soon.

 

[outlaw fab shop]

could the rotating assebly be balanced
mark

 

[65ShelbyClone]

Yes and it does help if it's dynamically balanced for the target RPM. Lightening the crank counterweights and using a lighter rod and piston will help further, although I'm not sure how much lighter those parts can be made from where they are now.

The way I see it, the rod journal is getting pushed forward by the rod and the chain is pulling backward on the PTO during the power stroke. My suspicion is that the crank flexes more on the outside of the rod journal and eventually breaks along that edge toward the crank centerline.

 

[Strigoi]

MDB, when are you getting more of the girdles for the cases?

 

[minidragbike]

MDB, when are you getting more of the girdles for the cases?

My buddy is really slow at making them. Had some 1 month ago, sold out in 24 hours. He says he will have some made in another week.

 

[65ShelbyClone]

Are those the girdles that get welded onto the block?

 

[outlaw fab shop]

My buddy is really slow at making them. Had some 1 month ago, sold out in 24 hours. He says he will have some made in another week.

pictures for the new guy????

 

[korndog]

Yes and it does help if it's dynamically balanced for the target RPM. Lightening the crank counterweights and using a lighter rod and piston will help further, although I'm not sure how much lighter those parts can be made from where they are now.

The way I see it, the rod journal is getting pushed forward by the rod and the chain is pulling backward on the PTO during the power stroke. My suspicion is that the crank flexes more on the outside of the rod journal and eventually breaks along that edge toward the crank centerline.

I think Pronova has had very good success balancing clone cranks. It seems to help.

Are those the girdles that get welded onto the block?

No, they are not welded to the block. They are made by a local guy, and bolt on.

 

[korndog]

pictures for the new guy????

Here ya go:

 

[outlaw fab shop]

Here ya go:

how much???:shrug:

 

[Strigoi]

i think he wanted $80 each for the last bunch.

 

[Strigoi]

My buddy is really slow at making them. Had some 1 month ago, sold out in 24 hours. He says he will have some made in another week.

post them on here or FB when you get more. i'm definitely interested in one.

 

[minidragbike]

OK will do
This guy is so slow at making them, I have about 5 people waiting on them to be done.